Hydrangea Report – March 6th

Hydrangea Report – March 6th

On Cape Cod we don’t care so much about about “Wind Chill temperatures” – we want reports on “Hydrangea Kill temperatures.” Knowing that our beloved Hydrangea macrophylla form their flower buds the previous summer, we all want those buds to make it through the winter so that our shrubs will come into bloom in the coming season. And since winter temperatures are more variable lately, alternating from unusually warm and then plunging down to frigid, we’re even less sure about Hydrangea flowering than we used to be.

Many of us have hydrangeas that have green buds that have been opening as if spring had arrived. We worry that last weekend’s plunge down to 12 degrees or colder might have ruined the flowering again this summer.

Bottom line? It’s still too early to tell. The fact that the buds might still be green are not a sure sign that they are still OK. Sometimes cold temperatures damage such buds to such an extent that although they look as if they have life, they never continue to open and develop. Only time will tell.

If you did wrap some of your shrubs as I did for the last weekend, be sure to remove those wrappings fairly soon. The warm sun at this time of year might actually accelerate a wrapped shrub’s bud opening, and then when you do remove the coverings the new growth will be even more vulnerable.

I wrapped two of my plants with blankets covered by a tarp. I have no idea if this will have helped or not.

I wrapped two of my plants with blankets covered by a tarp. I have no idea if this will have helped or not.

Some plants still have buds that look green but they also have a bit of blackness that wasn't there before last weekend. Only time will tell if the germ of the flower is still alive here.

Some plants still have buds that look green but they also have a bit of blackness that wasn’t there before last weekend. Only time will tell if the germ of the flower is still alive here.

Many of my plants have had buds that look like this since the fall. Again, there's no way of knowing if these are still viable or not. It's wait and see for these plants...

Many of my plants have had buds that look like this since the fall. Again, there’s no way of knowing if these are still viable or not. It’s wait and see for these plants…


  1. Diana Crighton on March 9, 2017 at 7:21 am

    I truly appreciate the information you provide. I always read every newsletter. This also helps me think about which type of hydrangea to purchase. Thank you !

  2. Jane Simpson on March 9, 2017 at 8:20 am

    Hi CL – I’d like to transplant some hydrageas. How soon do you think I could do that?

    • CLFornari on March 9, 2017 at 8:31 am

      Jane – a good time to transplant Hydrangeas is in April.

  3. Melissa Brown on March 9, 2017 at 10:24 am

    Thanks for the information. I have hydrangeas on an unheated porch that that actually have leaves.This coming weekend won’t help much either. Love you reports and Nan’s newsletter – look forward to everyone!

  4. Illene Brooks on March 9, 2017 at 12:04 pm

    Hi Nan. I just love all your reports, even the little tidbits. Wishing you and the gang, a very successful year. Happy Speing. ???????????

  5. Jane Simpson on March 9, 2017 at 12:09 pm

    Thanks for the prompt response. I love your column!

  6. shelly stirling on March 9, 2017 at 3:00 pm

    Hi, Country Garden folks!
    Thank you for the Hydrangea update. It is always a waiting game around here!!!
    I find that my Limelight Hydrangeas are fine after a frost and low temp nights. They don’t bud up until much later in the season. This variety is fabulous for the Cape. The plants grow to over 7’and the ” flowerettes” are ginormous. Limelights produce from mid summer until late fall!!! Last year, some blue and pink varieties produced a few flowers, but not many, depending on their location. Other blues did not produce at all, depending on when they put buds out. The earlier the bud formation,the worse the outcome. Weather around here is like the proverbial “box of chocolates!!”

    • CLFornari on March 9, 2017 at 5:32 pm

      You’re right – Limelight, being one in the paniculata species it always forms flower buds on new wood. As such, they haven’t even begun to form their flowers at this time of year. But the blue and pink lace caps and mopheads made their flower buds last year in August…which is why they are vulnerable to cold. And of course the erratic temperatures of warm/cold/warm/cold that we’ve had the past few years are the worst because they cause those buds to swell early and then freeze. If only someone would breed a blue-flowered Hydrangea paniculata! He/she would make a fortune!

  7. PATRICIA Mcdonald on March 10, 2017 at 12:54 pm

    Oh pray we have flowering hydrangeas this year!
    Thanks for the update!

    • CLFornari on March 10, 2017 at 1:18 pm

      Fingers crossed! It’s good we’re getting some snow – that might protect a few of the lower buds from tomorrow’s cold snap.

  8. Paula on March 23, 2017 at 5:27 pm

    Our tarp blew off the plants the 21st! My husband said “enough is enough” with covering and uncovering these plants………….. I can only hope the hydrangeas will flower the correct time or at least just flower! Remember last year, we had flowers late in the season and all the way up to Thanksgiving! As the saying goes: WELCOME TO CAPE COD. CL, when do you think we should fertilize this year?

    • CLFornari on March 23, 2017 at 8:43 pm

      You can apply Holly-tone in April. And if you need to mulch, a good thing to do before adding a layer of mulch is a light application of compost or composted manure. Then an inch or two of mulch on top. I found that covering my Hydrangeas just made them look worse so I won’t do it again.

  9. Karen Baker on May 28, 2017 at 5:37 pm

    hi CL I am poring over the hydrangea pruning articles, because once again, I am faced with the comments about how the hydrangeas at such and such a location, “used to flower so well” ( apparently before I took over pruning 2 years ago)…and now once again it is looking like the buds from last year…I haven’t touched them since last july,I have read never to prune after august first), when I cut out all the dead sticks that didn’t flower last summer…are looking pretty sparse as far as buds…did it happen again…did we get another spring cold snap? I always look to you for my hydrangea pruning advice…these are a light blue variety, maybe Domotoi, very robust foliage and very large plants…Aargh this hydrangea pruning is so hard here!

    • CLFornari on May 28, 2017 at 6:17 pm

      First of all, you are NOT to blame for any hydrangea flowering for the past two years. We had hydrangea-bud-killing weather two years in a row, but last year in SPADES. Secondly, climate change has indeed had a profound effect on our blue hydrangea blooms because we’ve seen very warm falls, followed by sudden cold snaps in the winter. So hydrangea buds have swelled in November and December thinking it was spring, only to be zapped by falling temps in Feb, March or even April.

      That said, this past winter wasn’t so bad for many hydrangeas! I have about 85% in great shape with flowers already showing. YAY! But in my travels to other properties I see that this good fortune is spotty. Some people have “old canes” with many leaves and developing flower buds, while others have some and occasionally there are shrub with little to no growth off of those old stems.

      If you haven’t touched them since July, you are in no way responsible for the lack of flowers.

      Basically, we look at our lace cap and mop heads in May and any cane that doesn’t have green leaves by the third week in May has died back. Sometimes this is a matter of wind exposure, and other times it’s in the genetics of the plant. NOT ALL BLUE FLOWERING HYDRANGEAS ARE EQUAL GENETICALLY when it comes to bud hardiness. So your clients might want to have some other varieties planted. I have been very impressed with Enchantress (Monrovia) and BloomStruck (Endless Summer group) on my property.

      I haven’t seen great blooming from Domotoi myself. The one I’d really stay away from is Big Daddy – that is not genetically prone to cold hardiness!

      Perhaps your client has hydrangeas in a wind tunnel or other exposed location? Any chance of relocating or planting a wind screen?

  10. Karen Baker on May 28, 2017 at 6:34 pm

    thanks CL just hearing it from you made me feel better…the area in question is very exposed, and has a picket fence around two sides…but exposure is exposure! will see what happens this year…I did recently[in the past week} take back dead canes to the stronger growth lower on the canes, but tried to be very conservative knowing the flower buds are on the uppermost portion of the canes

    • CLFornari on May 28, 2017 at 7:07 pm

      You’ve done all that you can!

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